Polishing plate



p 1969 J. J. BOUVIER 3,464,166

POLISHING PLATE Filed May 23, 1967 INVENTOR.

Jakrz JfBouz/ier ATTORNEYS.

Unitcd States Patent US. Cl. 51-209 8 Claims ABSTRACT OF THE DISCLOSURE Small abrasive faced studs (particularly diamond faced) are resiliently held in a drive plate so that gentle abrasion and minimum scratching of work will result during use.

This invention relates to a metal plate carrying a plurality of abrasive faced studs which are carried thereby and resiliently supported thereon intended primarily for light abrasive or polishing use. The invention relates particularly to such a device where the abrasive facing of the studs is diamond impregnated.

The use of my device enables me to secure an effective but more gentle abrasive action than has been possible with previous devices intended for this purpose and permits more effective use to be made of costly diamond abrasives though it is also applicable to the use of the cheaper abrasives such as silicon carbide or fused alunnna.

In the manufacture of my device, I use a thin metal plate which may be resiliently attached to a heavier drive plate and in my case has resiliently attached to it small abrasive faced studs or buttons which are carried by bolts which extend through springy rubber layers which may be in the form of grommets or bushings which are held in place in holes extending through the metal plate. The nature of my device and its method of assembly will be readily understood in connection with the accompanying drawings where:

FIG. 1 is a face-on view of the abrasive face of the device;

FIG. 2 is a cross section of the device taken along line 22 of FIG. 1;

FIG. 3 is an enlarged cross sectional view of one of my studs as generally shown in FIG. 2;

FIG. 4 is an enlarged cross sectional view of a stud in an alternative structure of my invention; and

FIG. 5 illustrates a method of forming an abrasive face on one of my studs.

In these drawings, 1 indicates my thin metal plate for which I usually use 0.025 inch thick spring steel sheet. Through this I provide numerous holes as follows: Through a characteristic plate seven inches in diameter I provide thirty-five holes 13 for insertion of my abrasive studs and four holes 5 for insertion of drive pins or bolts 3 which extend about an inch beyond plate 1 and are are there screwed into a circular cast iron plate 2 which may be attached to a suitable drive shaft (not shown) which may extend through a central hole 7 in the drive plate 2. A corresponding hole at the center of plate 1 permits introduction of a stream of cooling water during operation of my device. Bolts 3 should have an easy slip fit through holes 5 where bolt head 6 keeps them from slipping completely through. On the opposite side of plate 1 between it and plate 2, the bolt 3 is surrounded by a coiled compression spring 4 which keeps plate 1 firmly against bolt head 6.

By this arrangement, plate 1 is enabled to accommodate its positon to variations in the surface being ground. While I usually use four bolts for this attachment, three may be used if desired.

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As indicated in FIGS. 2 and 3, I insert through each hole 13 a resilient double flanged rubber bushing or grommet 12 such as is used in the electrical industry to protect wiring where it passes through a plate which might make damaging electrical contact with the wire. ThlS bushing overlaps plate 1 on both sides of the plate and is thus held firmly in place in it. Through each such bushing, I pass the stem of a bolt 10 carrying on its head 8 my abrasive impregnated facing 9.

In place of the flanged grommet, I may alternatively use the construction shown in FIG. 4 in which resilent rubber sheets or washers 12A are inserted between my bolt 10 and sheet 1 on both sides of sheet 1. When washers are used they are held in place by the bolt and nut 11 whereas when larger rubber sheets are used it is advantageous to also cement these rubber sheets to the steel plate using one of the adhesives well known to the industry for such puropses.

I normally use bolts on which the flat faced head 8 is circular though I may cut away one or more sides thereof to permit holding it firmly while nut 11 is screwed down to keep the bolt in place. However, hexagonal or other shaped heads may be used. I select a head shape however such that no diameter across it is more than 1.5 times the minimum diameter thereof as in that way any irregularity of abrasive action is minimized. These relative dimensions obviously apply also to the abrasive facing which covers the end face of the bolt.

For insertion of my bushings 12, I provide holes /2 inch in diameter through plate 1. These bushings have a inch diameter hole in their center through which I insert my bolt 10 with a screw shank inch long.

Before my studs are inserted in these bushings, I attach abrasive facings 9 to them. These are applied individually though several may be applied simultaneously with proper apparatus. In one method of operation I fabricate small cylindrical pieces of my abrasive bonded with powdered metal by means familiar to the art and braze these to the heads of my bolts.

In another method of preparing these studs as shown in FIG. 5, I prepare a mold 15 of graphite in which I drill concentric holes 16 and 17. I countersink the upper end of hole 17 to match the bevel on the head of screw 10A but not so deeply as to prevent the head of the screw from extending up into hole 16. After placing screw 10A in hole 17 as shown, I place powdered metal bond 18 around the head of the screw in hole 16 to completely cover the screw head to a depth of perhaps inch. This powder may be for example 10% tin and copper, both being mesh and finer or other metal powders familiar in the art may be used. On top of layer 18 I next insert layer 18 composed of similar metal bond admixed with my abrasive which may be of diamonds alone or diamonds admixed with other softer materials. I normally make layer 19 approximately A to inch deep to conserve my abrasive though this is obviously a matter of choice as is the mesh size or ratio of diamonds to other abrasive used.

I finally insert plunger 20 in hole 16 above the abrasive mix and while the entire mold assembly is heated to 1800-1950 F. for 2 to 4 minutes I apply a downward pressure of from 10 to 50 pounds to compress the constituents of layers 18 and 19 and cause them to adhere firmly to one another and to the head of screw 10A. The mold and its contents are then cooled to room temperature and the finished stud removed.

The size of my diamonds varies depending upon the desired operation, being as coarse as 20 to 25 mesh for rough work and down to 600 mesh (30 microns) for fine polishing. Likewise I may admix my diamonds with any desired proportion of other softer materials such as tungsten carbide or boride or even granular glass though the proportion of diamond is usually from 2 to 25% by volurne of the mix including bond.

I prefer that my abrasive facings should not be over 1" across and preferably from to 1 inch in diameter and about 75 thick. Care must be taken that the relative heights of bolt heads 6 are not so great as to prevent abrasive faces 9 from making contact with the work to be ground.

While the embodiment described above is my preferred method of operation, it is within the scope of my invention to omit the backing plate of cast iron and drive my spring steel plate 1 by directly bolting it at its center to the drive shaft. This gives a structure which is less springy and yielding than when the back up plate is used but it nevertheless gives a polishing action freer from scratching than where rigid abrasive wheels are used. In this case abrasive faced studs should be used in conjunction with the steel plate just as shown here.

Previous polishing plates wherein abrasive blocks from 2 x 4 inch to 2 x 1 inch have been soldered, screwed or otherwise rigidly fastened to the working face of a metal plate, oriented in miscellaneous directions, have much more tendency than do mine, to dig into and scratch the work being polished.

My grommets, in addition to permitting slight vertical displacement of my abrasive facings, also permit slight lateral displacement which, when combined with the re-,

silient, spring mounted plate 7, provides a relatively firmly held series of abrasive grinding faces, each of which may be displaced slightly, independently of the other faces during the grinding operation, or, displacement of a series of abrasive facings in unison, may be effected on a broader scale by a slight displacement of the spring mounted face 1 depending upon the configuration of the work piece being abraded.

Also while my invention is concerned primarily with rotatable devices, metal plates equipped with my resiliently held abrasive studs may be utilized in reciprocating polishers within the broad scope of my invention.

It should also be understood that while in the foregoing discussion I have described the use of metal powder bonds, the use of phenolic resin bonds as commonly applied in the industry is within the scope of my invention. In that case I prefer to form the resin bonded facings for my studs separately and after curing, fasten them to my stud faces using adhesive cements common in the art.

As my invention I claim:

1. A polishing device comprising a flexible metal plate having inserted through holes there-in abrasive faced members held in place by resilient means, said members having their abrasive faces respectively at the same end thereof.

2. The polishing device of claim 1 wherein said resilient means are grommets.

3. The polishing device of claim 2 wherein each abrasive face has a maximum dimension not more than 1.5 times its minimum width.

4. The device of claim 1 wherein said abrasive faces consist of from 2 to 25% by volume of diamonds with a metal bond therefor.

5. Polishing device comprising a member rotatable in a given plane and having aflixed thereto via resilient means a second member rotatable with the first, said second member rotatable in a variable plane and about a different axis with respect to the plane of rotation of said first member, said second member having inserted through holes therein abrasive faced members held in place by a second resilient means, said members having their abrasive faces respectively at the same end thereof.

6. The polishing device of claim 5 wherein said second resilient means are grommets.

7. The polishing device of claim 6 wherein each abrasive face has a maximum dimension not more than,1.5 times its minimum width.

8. The device of claim 5 wherein the said abrasive faces consist of from 2 to 25 by volume of diamonds with a metal bond securing them to said member.

References Cited UNITED STATES PATENTS 19,569 3/1858 Lindsay 51-209 X 1,012,227 12/1911 Stitch. 1,180,260 4/1916 Grice 5l-209 X 1,217,090 2/1917 Gowlland 51204 1,290,990 l/1919 Hickey 51-209 1,952,003 3 1934 Walsh 51-209 3,121,982 2/1964' Miller 51-209 LESTER M. SWINGLE, Primary Examiner 

